Band filter press

ABSTRACT

A cleaning arrangement comprising several fan spray nozzles and scrapers for cleaning both surfaces, and the entire width, of the filter band, in a vertical filter press, between the outlet end of the band from the filter plates and the drive roller for the band.

1 1 3,655,055 [451 Apr. 11, 1972 United States Patent Van Egdom et a1.

[56] References Cited UNITED STATES PATENTS [54] BAND FILTER PRESSFOREIGN PATENTS OR APPLICATIONS 1,080,461 8/1967 GreatBritain.........................l00/198 [22] Filed: July 2, 1970 PrimaryExaminer-Reuben Friedman Assistant Examiner-T. A. GrangerAttorney-Michael S. Striker 21-1 App]. No.: 52,045

[30] Foreign Application Priority Data Dec. 9, 196 9Germany......................P l9 6] 608.1 ABSTRACT A cleaningarrangement comprising several lan spray nozzles 33/00 and scrapers forcleaning both surfaces, and the entire width, 100/ 198; 210/224, 225 ofthe filter band, in a vertical filter press, between the outlet end ofthe band from the filter plates and the drive roller for the band.

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11 Claims, 2 Drawing Figures PATENTEDAPR 1 1 1912 FIG] I I VVENTORG 7 vBAND FILTER PRESS BACKGROUND OF THE INVENTION The invention relates to acleaning arrangement, in a band filter press, for cleaning the filterband.

In vertical filter presses, having a number of filter plates arrangedone over the other, the cloth filter, which is in the form of an endlessband, or belt, is pulled zigzag along the path defined by the filterplates by a drive roller that is located after the last filter plate.This known arrangement has the disadvantage that the filtration residue,which clings to, or is held in, the cloth band, is pressed into the bandby the pressure roller, which is held against the drive roller. As aconsequence, it is more difficult to clean the band after the driveroller with a spray arrangement. Moreover, the pull of the drive rolleron SUMMARY OF THE INVENTION An object of the invention is a cleaningarrangement in a filter press located between the outlet end for theband, at the last filter plate, and the drive roller.

Another object of the invention is a cleaning arrangement of this kindhaving mechanical means, such as one or more scrapers and/or stationaryor rotating brushes, and/or spray means.

The invention broadly comprises in a filter press an elongated, such asan endless, filter band of fluid permeable material and a plurality ofrelatively movable filter elements that define for the filter band apath having an outlet end, and drive means spaced from the outlet endand arranged to move the band along a path, whereby it collectscontaminates, and an arrangement for cleaning the filter band betweenthe outlet end and the drive means so that at least some of thecontaminates are removed from the band ahead of the drive means.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a vertical filter pressequipped with the cleaning arrangement of the invention shown in sideview; and

FIG. 2 is a side view in cross section of the cleaning arrangement.

DESCRIPTION OF THE PREFERRED EMBODIMENTS exampleare arranged between thecolumns 10 and the lifting table 12, which is connected to the upper endof the lifting cylinder 6. The filter plates are shown in the openposition of the press, the lifting cylinder 6 being in its lowerposition. The frames of the filter plates are provided with arms 14,which at their ends rotatably support guide rollers 15. An endlessfilter band 16 is guided zigzag between the filter plates, islet to thewash tank 8, passes over a regulating roller 17, which is adjusted tokeep the band straight, and finally passes through a tensioning rollerarrangement 18 before it is returned to the press proper.

As seen in FIG. 2, the band 16 moves in the direction of the arrow fromthe last guide roller 15 into the wash tank 8, which has a lower guideroller 19 beneath the last roller 15, which constitutes for the band theoutlet end of the press. Before the filter band passes under the roller19 two fan spray nozzles 20 and 21 clean the band. The two spraysoverlap at the band so that the entire width of the band is sprayed witha cleaning medium, which can be filtrate from the filtering operation.As a consequence, the filter band is thoroughly prewashed, whereby thefiltration residue after having passed by the spray nozzles 20 and 21 isremoved by scrapers 22 and 23. In order to prevent the residue fromfalling back onto the filter band, the scraper 22 has a plate 24 withgutter-like deflectors 25 that diverge towards the bottom of the plate24, so that the scraped residue sliding down the deflectors isdischarged at the deflector ends 26 outside of the width of the band.The scraper 23 does not require this arrangement, because the scrapedresidue falls directly into the wash tank 8 and can be carried offthrough the short discharge pipe 27.

After the filter band leaves the roller 19, scrapers 28 and 29respectively clean the upper and lower band surfaces, and two additionalfan spray noules 30 and 31 spray the band surfaces, in order to removethe last of the residue. The band then winds around approximatelythree-quarters of the circumference of a drive roller 32, the drive ofwhich is not shown. A pressure roller 33, pushed by a spring, isadjustably squeezed against the drive roller 32. for part If thefiltration residue is washed with filtrate in the wash tank 8, becausethe solid matter is recovered, then it is advisable to rewash the filterband with water in a rewash tank 34 containing the pressure roller 33.The bottom of this tank is inclined and has a discharge opening 36. Twofan spray nozzles 37 spray water on respective sides of the band. Thecleaned band then moves over a guide roller 38 to the regulating roller17.

The rewash tank 34 and the fan sprays 37, although not an essential partof the invention, are advantageous when the band 16, for reasons ofeconomy, is cleaned with filtrate, if the filtration residue iscollected. The washing medium in the rewash tank 37 can, in this case,be water. Alternatively, water can be supplied to two oppositelydisposed spray nozzles associated with the wash tank 8, should filtratebe used fopart of the washing.

In accordance with the invention, one, more, or all of the scrapers canbe replaced by stationary or rotating brushes that are positionedimmediately in front of, or after, the associated fan spray nozzles.

The cleaning arrangement of the invention can comprise only spraynozzles or only mechanical means, such as scrapers or brushes, or anydesired combination of these, in dependence on the kind of cleaningaction required.

The fan spray nozzles have proved to be particularly advantageous,because the previously used pipes with spray openings only sprayed thecloth filter along incremental areas that extended in the direction ofband movement and were separated by a distance corresponding to theseparation between adjacent spray openings in the pipe. Consequently,there were regularly spaced incremental areas of the band that were notsprayed.

The press operates in the following manner. Liquid to be filtered issupplied to the space between the filter band add the next upper filterplate 13, whereupon the press is closed, and the filtrate squeezedthrough the cloth band 16 is collected.

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types ofband filter press differing from the type described above.

Without further analysis, the foregoing will so fully revel the gist ofthe present invention that others can be applying current knowledgereadily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this inventionand, therefore, such adaptations should and are intended to becomprehended within the meaning and range of equivalence of thefollowing claims.

What is claimed as new and desired to be protected by Letters Patent is:

1. In a band filter press, a filter arrangement having an inlet and anoutlet for an endless filter band; an endless filter band offluid-permeable material; guide means for guiding said endless filterband along a filtering path from said inlet through said filterarrangement and out through said outlet and then along a return pathback from said outlet to said inlet of said filter arrangement; drivemeans arranged along said return path spaced from said outlet andengaging said filtering band to move the same along said return pathfrom said outlet back to said inlet; and cleaning means including awashing arrangement located along said return path between said outletand said drive means and serving for cleaning said endless filter bandso that said band is washed and cleaned before being engaged by saiddrive means.

2. An arrangement as defined in claim 1, said washing arrangementincluding means for conveying a stream of washing medium through saidband across the entire width thereof.

3. An arrangement as defined in claim 1, said washing arrangementincluding at least one mechanical cleaning means for cleaning the entirewidth of the band. V

4. An arrangement as defined in claim 3, wherein said mechanicalcleaning means are at least one brush.

5. An arrangement as defined in claim 4, wherein said brush rotates soas to increase the cleaning action.

6. An arrangement as defined in claim 3, wherein said mechanicalcleaning means are at least one scraper.

7. An arrangement as defined in claim 6 further comprising meansassociated with said scraper for preventing sraped-off contaminates fromfalling back onto the band.

8. An arrangement as defined in claim 2, said washing arrangementincluding at least one means for producing a fan spray of washing mediumthat covers the entire width of the band.

9. An arrangement as defined in claim 8, said washing arrangementincluding at lemt one mechanical cleaning means for cleaning the entirewidth of the band.

10. An arrangement as defined in claim 9, wherein said path has an inletend and further comprising rewash means located between said inlet endand said drive means for rewashing the band already at least partlycleaned by said washing arrangement.

11. Cleaning apparatus for cleaning the continuous filter band of a bandfilter press comprising, in combination, (a) a band filter press with acontinuous filter band and a wash tank; (b) first spray and scrapermeans constructed and arranged to clean said continuous filter bandafter use for filtration in said filter press and before engagement witha first guide roller for said filter band within said wash tank; and (c)second spray and scraper means within said wash tank constructed andarranged to clean said continuous filter band after engagement with saidfirst guide roller and before engagement with a drive roller for saidcontinuous filter band, whereby said continuous filter band isessentially cleaned of residue before engagement with said drive roller.

1. In a band filter press, a filter arrangement having an inlet and anoutlet for an endless filter band; an endless filter band offluid-permeable material; guide means for guiding said endless filterband along a filtering path from said inlet through said filterarrangement and out through said outlet and then along a return pathback from said outlet to said inlet of said filter arrangement; drivemeans arranged along said return path spaced from said outlet andengaging said filtering band to move the same along said return pathfrom said outlet back to said inlet; and cleaning means including awashing arrangement located along said return path between said outletand said drive means and serving for cleaning said endless filter bandso that said band is washed and cleaned before being engaged by saiddrive means.
 2. An arrangement as defined in claim 1, said washingarrangement including means for conveying a stream of washing mediumthrough said band across the entire width thereof.
 3. An arrangement asdefined in claim 1, said washing arrangement including at least onemechanical cleaning means for cleaning the entire width of the band. 4.An arrangement as defined in claim 3, wherein said mechanical cleaningmeans are at least one brush.
 5. An arrangement as defined in claim 4,wherein said brush rotates so as to increase the cleaning action.
 6. Anarrangement as defined in claim 3, wherein said mechanical cleaningmeans are at least one scraper.
 7. An arrangement as defined in claim 6further comprising means associated with said scraper for preventingsraped-off contaminates from falling back onto the band.
 8. Anarrangement as defined in claim 2, said washing arrangement including atleast one means for producing a fan spray of washing medium that coversthe entire width of the band.
 9. An arrangement as defined in claim 8,said washing arrangement including at least one mechanical cleaningmeans for cleaning the entire width of the band.
 10. An arrangement asdefined in claim 9, wherein said path has an inlet end and furthercomprising rewash means located between said inlet end and said drivemeans for rewashing the band already at least partly cleaned by saidwashing arrangement.
 11. Cleaning apparatus for cleaning the continuousfilter band of a band filter press comprising, in combination, (a) aband filter press with a continuous filter band and a wash tank; (b)first spray and scraper means constructed and arranged to clean saidcontinuous filter band after use for filtration in said filter press andbefore engagement with a first guide roller for said filter band withinsaid wash tank; and (c) second spray and scraper means within said washtank constructed and arranged to clean said continuous filter band afterengagement with said first guide roller and before engagement with adrive roller for said continuous filter band, whereby said continuousfilter band is essentially cleaned of residue before engagement withsaid drive roller.